I have had a few variations of the PC60, all of which were excellent quality and very light. I havnt had any of the more recent models (after migrating back to Macs) so cant really help there.
The Tagan PSU I had (and consequently built into quite a few other systems) was 480Watt, standard ATX PSU. It really is an excellent power supply.
If you havn't heard of it already,
www.quietpc.com is pretty good for your quiet components I have found.